1. Field of the Invention
The present invention relates to a wiper strip, a wiper blade having the wiper strip and a designing method of the wiper strip.
2. Description of Related Art
A wiper strip of a vehicle wiper wipes water droplets, which adhere to a glass surface, so that a thin and generally uniform water film is formed by the wiper right after the wiping on the glass surface right after the wiping. As a result, refraction and diffuse reflection of the light at the water film right after the wiping are reduced, thereby resulting in an improved wiping performance. For example, according to the technique recited in Japanese Unexamined Patent Publication No. H07-246916, a contact angle of a wiper strip of the wiper (an angle defined between a lip portion of the wiper strip and the glass surface) is appropriately set to improve the wiping performance.
However, the appropriate setting of the contact angle for improving the wiping performance has been already standardized, and it has been demanded to further improve the wiping performance. In order to meet such a demand, designers of the wiper strip have tried to find appropriate design factors (e.g., a material of the wiper strip, shapes and sizes of corresponding parts of the wiper strip) based on experience and wisdom of the designers and have produced prototypes of the wiper strip and have tested the same. However, it has not been clear for the designers which one or more of the design factors actually contribute to the improvement of the wiping performance in what way. Thus, it has been difficult to obtain a wiper strip having a higher performance. Therefore, although the contact angle of the wiper strip is appropriately set, the material of the wiper strip and the shapes and sizes of the corresponding parts of the wiper strip are still conventional ones.